Chukchi Sea | sea, Arctic Ocean | Britannica.com sea, Arctic Ocean Alternative Titles: Chukchee Sea, Chukotskoe Sea, Chukotskoye More Similar Topics Caspian Sea Chukchi Sea, also spelled Chukchee, Russian Chukotskoye More, part of the Arctic Ocean , bounded by Wrangel Island (west), northeastern Siberia and northwestern Alaska (south), the Beaufort Sea (east), and the Arctic continental slope (north). It has an area of 225,000 square miles (582,000 square km) and an average depth of 253 feet (77 m). The sea is navigable between July and October both eastward and westward from the shallow Bering Strait , and ice-bearing currents flow southeastward along the Siberian coast. Seals of several species and walrus are indigenous , and whales and many seabirds are summer visitors.

Learn More in these related articles: in Arctic Ocean: Oceanography ...side of the Arctic Ocean is of a normal width (approximately 40 miles), the Eurasian sector is hundreds of miles broad, with peninsulas and islands dividing it into five main marginal seas: the Chukchi, East Siberian, Laptev, Kara, and Barents. These marginal seas occupy 36 percent of the area of the Arctic Ocean, yet they contain only 2 percent of its water volume. With the exception of... 1 Reference found in Britannica Articles Assorted Reference marginal seas of the Arctic Ocean (in Arctic Ocean: Oceanography ) Article History Corrections? Updates? Help us improve this article! Contact our editors with your feedback. MEDIA FOR: You have successfully emailed this. Error when sending the email. Try again later. Edit Mode Submit Tips For Editing We welcome suggested improvements to any of our articles. You can make it easier for us to review and, hopefully, publish your contribution by keeping a few points in mind. Encyclopædia Britannica articles are written in a neutral objective tone for a general audience. You may find it helpful to search within the site to see how similar or related subjects are covered.

Any text you add should be original, not copied from other sources. At the bottom of the article, feel free to list any sources that support your changes, so that we can fully understand their context. (Internet URLs are the best.) Your contribution may be further edited by our staff, and its publication is subject to our final approval. Unfortunately, our editorial approach may not be able to accommodate all contributions. Submit Thank You for Your Contribution! Our editors will review what you've submitted, and if it meets our criteria, we'll add it to the article. Please note that our editors may make some formatting changes or correct spelling or grammatical errors, and may also contact you if any clarifications are needed. Uh Oh There was a problem with your submission. Please try again later.

Close Date Published: July 20, 1998 URL: Access Date: January 18, 2017 Share Sea Ice Conditions in the Chukchi and Beaufort Seas Sea Ice Conditions in the Chukchi and Beaufort Seas Copy the URL for use in an RSS reader: Share Sea Ice Conditions in the Chukchi and Beaufort Seas A science brief The third in our series of science briefs and analyses, this report was prepared for The Pew Charitable Trusts U.S. Arctic Program by Andrew R. Mahoney and released in November of 2012. Download the complete brief » INTRODUCTION The Chukchi and Beaufort seas lie north of Alaska and together contain the entire U.S. Arctic domain. Nominally, the two seas are separated by Point Barrow, the northernmost point of the North American mainland. Away from the coast, the boundary between the Chukchi and Beaufort seas is typically defined by the regional bathymetry.

The Chukchi Sea is dominated by a broad, shallow shelf (the Chukchi Shelf) mostly less than 50 meters (160 feet) deep with shoals such as Hanna Shoal and Herald Shoal rising to around 20 m. Conversely, water shallower than 50 m in the Beaufort Sea occupies only a narrow strip less than 100 km from the coast. Most of the Beaufort Sea is greater than 1,000 m deep and is part of the Canada Basin. There are other geographic differences between the Chukchi and Beaufort seas, such as latitude and coastal confinement. These factors, along with the Chukchi’s connection to the Pacific Ocean, play a large role in defining the sea ice conditions in the two seas and how they might respond to ongoing changes in the Arctic climate. SUMMARY Differences in geographic setting and bathymetry between the Chukchi and Beaufort seas lead to marked differences in the character of sea ice in these two regions. Due to its more southerly location and connection to the Pacific Ocean, the Chukchi Sea experiences a longer open water season than the Beaufort.

In addition, due to the combination of a thinner ice pack and a coastline that offers the opportunity for open water creation under almost any drift direction, sea ice in the Chukchi Sea is more mobile and changeable than sea ice in the Beaufort. This is also reflected in the greater extent of landfast sea ice in the Beaufort Sea. These differences represent important considerations for offshore activities in the U.S. Arctic domain. In particular, operational experience gained in one sea may not be directly applicable to the other. It is also important to recognize that the extent of our understanding of the sea ice environment for the Chukchi is different from the Beaufort. This is partly because there is a shorter history of commercial interest in the Chukchi Sea than the Beaufort Sea and therefore fewer baseline sea ice data are available. In addition, the Pacific sector of the Arctic is undergoing some of the most rapid environmental changes on Earth, which reduce the value of data from previous decades for planning and design purposes. However, Arctic stakeholders, including academics, industry executives, state and federal regulators, and local communities are rising to the challenge, and there is currently an unprecedented number of active observing programs in the region.

RELATED IMAGES Chukchi Sea | Audubon Alaska Audubon Alaska Audubon Alaska works to protect habitat for eiders, walrus, and other wildlife in the Chukchi Sea. Bearded Seal Midnight Sun on the Chukchi Sea Photo: MiloBurcham What's the Arctic Ocean like throughout the summer? Find firsthand accounts from field reserachers, underwater sound recordings, and more on Audubon Alaska's Vital Arctic Ocean Areas Storymap . See Audubon Alaska's maps of important wildlife areas in the Chukchi Sea for eiders, bowhead wales, walrus, and other birds and wildlife. (File size: 13M) Audubon Alaska submitted these maps and comments to the Bureau of Ocean Energy Management in April 2016. The Chukchi Sea, off the coast of northwest Alaska, is one of the most productive ocean ecosystems in the world. Its vast, shallow sea floor and seasonal ice cover provide nutrients and pristine habitat for a multitude of organisms, ranging from walruses to ice seals to whales to millions of seabirds to the top predator mammal, the polar bear. But the Chukchi Sea is changing dramatically.

The evidence of global climate change is evident here perhaps like no other place on earth. Sea temperatures are rising, shorelines are dramatically eroding, and summer sea ice is receding to historic lows. As sea ice retreats, there are substantial prospects for new industrial activities in the Chukchi, including commercial fishing, commercial shipping, and oil and gas extraction. Scroll down to read more about the magnificent wildlife of the Chukchi Sea, Audubon's position on balance in the Arctic, and how you can help protect the Chukchi Sea. Mammals of the Chukchi The Chukchi Sea is distinctly different from lower latitude seas and makes direct and important contributions to global ocean and climate systems. Ice in particular is a critical feature of the Chukchi. The ice edge produces a rich profusion of phytoplankton, which is the base of the food chain for all marine and coastal Arctic wildlife and people, especially with a lack of sea floor predation by warmer water fish, such as salmon and pollock.

The Chukchi's shallow and highly productive sea floor allows bottom-dwelling prey (crustacea, mollusks, etc.) to flourish, creating a buffet for wildlife specialized to feed off the ocean floor, such as walrus, seals, gray whales, and deep-diving sea birds. Many of these species also rely on ice edges for resting, denning, and/or calving. Perhaps most famously, the Chukchi Sea is home to roughly half of America's polar bears, approximately 2,000 animals, or one-tenth of the world's population. Polar bears are integrally tied to sea ice for hunting, resting, breeding, and denning. Yet as the summer sea ice has retreated dramatically in recent years, especially off the coast of Alaska, polar bears are increasingly denning on coastal lands instead. The melting sea ice has also reduced the area available to polar bears for hunting seals, the bear's chief prey species, and is forcing bears to swim farther in search of food and denning sites. A September 2007 study from the United States Geological Survey forecasts a loss of two-thirds of the world's polar bears—and all of Alaska's polar bears—by 2050.

Other studies have documented polar bear drownings, smaller body size, lower cub survival rates, and cannibalism due to sea ice retreating. Based on this evidence and other scientific work, the polar bear was declared "threatened" under the Endangered Species Act (ESA) in 2008. The most common prey species of the polar bear is the ringed seal, one of the so-called "ice seals" of the Chukchi. Other Chukchi ice seals include ribbon, bearded, and spotted seals. True to their nickname, these seals are ice dependent, relying on ice edges to hunt and give birth to and nurse pups. In addition to seals, most of the Pacific walrus population uses the Chukchi Sea during the summer months. Unlike seals, walruses cannot swim indefinitely and rely on ice floes extensively for resting and as platforms from which to feed on mollusks and other benthic invertebrates. In recent years, as the ice retreated beyond the continental shelf, more than 10,000 walrus "haul out" on shore in Alaska and in Russia, and thousands of walruses have been killed in stampedes as the animals crowded onto the shoreline in these extraordinary numbers.

Walruses have also suffered from population declines as feeding and nursing their young have grown increasingly difficult. The US Fish and Wildlife Service is investigating listing the Pacific walrus under the ESA. The Chukchi is also important for whales. Endangered fin and humpback whales, and formerly endangered gray whales, feed in the Chukchi’s shallows, and up to 3,500 beluga whales use Kasegaluk Lagoon near Point Lay for feeding, calving, and molting. In addition, most of the western Arctic Ocean’s endangered bowhead whales, the most important subsistence and cultural resource of many Alaskan North Slope residents, migrate along the Chukchi coast. Birds of the Chukchi The bays, inlets, and river outlets lining the Chukchi also provide breeding, feeding, and staging areas for millions of shorebirds, seabirds, and waterfowl. At least 15 species on Audubon's Alaska WatchList use the Chukchi, including Spectacled Eiders , which are listed as threatened under the ESA, and Yellow-billed Loons , which have been found to warrant ESA listing (but are not a study priority).

There are small populations of Kittlitz’s Murrelets in the Chukchi Sea. Nests have been found inland in the DeLong Mountains and Lisburne Hills, and murrelets have been found up to 40-50 miles offshore, primarily in the Cape Lisburne area north of Point Hope. Kittlitz's Murrelets have undergone dramatic reductions in population in recent years. The US Fish and Wildlife Service decided not to list the species under the Endangered Species Act, but it remains to be seen how changes in climate will affect this species. Several globally and continentally significant Important Bird Areas (IBAs) are within the Chukchi, including a dozen IBAs on the US side of the Chukchi Sea and six more on the Russian side. Included among these are marine feeding areas for Northern Fulmars and Short-tailed Shearwaters and nesting and feeding areas for huge colonies of Common Murres and Thick-billed Murres. Ledyard Bay , an IBA just south of proposed oil and gas leases, is a Critical Habitat Area for Spectacled Eiders, listed as a threatened species under the Endangered Species Act (ESA).

In fact, most of the female Spectacled Eiders that breed on the Arctic Coastal Plain molt in Ledyard Bay. About 33,000 Spectacled Eiders and 500,000 King Eiders feed on mollusks and other bottom food in the shallow waters of the Bay. From April into November, nearly all of the breeding King Eiders from the US and Canada, plus many Russian breeding King Eiders, migrate through, stage, and forage in the eastern Chukchi. King Eiders utilize the shallow open polynas (openings in sea ice) of the Chukchi to dive for mollusks and other invertebrates in spring and early summer, prior to dispersing to breeding grounds in Canada and Russia and on Alaska’s North Slope. Oil and Gas Leasing in the Arctic Ocean Despite its spectacular wildlife, the Chukchi Sea is under intense pressure from prospective oil and gas development, especially as the sea ice melts. December 2013 was the deadline for a Chukchi Sea call for Information from the Bureau of Ocean Energy Management in preparation for a potential oil and gas lease sale in 2016.

See Audubon Alaska's maps of important wildlife areas in the Chukchi Sea for eiders, bowhead wales, walrus, and other birds and wildlife. (File size: 4M) A Big Step Forward... In January 2015, there was good news for parts of the Chukchi and Beaufort Seas: President Obama permanently withdrew several areas from oil and gas leasing . The areas the Administration chose to withdraw are important for subsistence, and provide key habitat for birds and wildlife. A number of other very important areas in the Arctic Ocean remain open to drilling. This action protects a portion of Audubon's recommended conservation area around Hanna Shoal , where sea ice lingers longer than in other places, providing important habitat for ringed, bearded , and ribbon seals and especially for walrus. Common and Steller's Eiders migration through here, and this is one of the only documented areas in U.S. waters where Ivory Gulls congregate. Sliding Backwards... In February of 2008, in its first lease sale in nearly 20 years, nearly three million acres in the Chukchi Sea were sold for over $2.6 billion.

The leased areas are roughly 50-60 miles from the northwest coast of Alaska. Audubon, in partnership with several Alaska Native and conservation groups, filed a lawsuit to block implementation of that lease sale and future exploratory activities.The court found that the agency had vastly underestimated the possible impacts of a large spill and ordered a revision of the assesment. In February 2015, the Bureau of Ocean Energy Management (BOEM) released the disappointing revision. The plan acknowledges a 75% chance of a major oil spill, which: could result in the deaths of large numbers of polar bears; could result in many thousands of seals, especially ringed seal pups, dying from oil exposure; could decimate bird populations and result in population-level effects for most marine and coastal bird species that would take more than three generations to recover; could kill 60,000 brant and have major impacts on the Pacific flyway brant population; could result in "large-scale mortality" for murres, puffins, kittiwakes, auklets, and shearwaters. Despite the potential for disaster, BOEM rushed through the process to approve the plan so Shell could start drilling.

Adjacent to the Chukchi Sea to the east, the Beaufort Sea is under similar development pressure, though courts have intervened. Shell Oil attempted exploratory drilling in the Beaufort close to the Arctic National Wildlife Refuge in 2012, but was plagued by a series of mishaps, including the grounding of the drill rig the Kulluk near Kodiak on New Year's Eve. Only one field in the near-shore outer continental shelf (OCS) of the Beaufort Sea, off the coast of Prudhoe Bay, is currently producing oil, though the State of Alaska has held several lease sales in the state-owned waters of the Beaufort Sea within three miles of shore. Balance in the Arctic: Audubon’s Position Although Audubon has not opposed oil and gas leasing and development in many areas of the Arctic, there are several places where natural values are so important, and/or where so little is known of the dynamic environment, that further development should not be allowed. The Chukchi Sea is one of those special places. Global climate change is a growing threat, and its effects in the Arctic are obvious and dramatic.

In 2014 the summer minimum polar ice pack was at the 6th lowest ever recorded. Some scientists predict that the permanent Arctic Ocean sea ice may be gone by 2040. With the disappearance of sea ice habitat, there has been a flurry of petitions and proposals to protect several of the Arctic's at-risk, ice-dependent marine mammals under the ESA. Given indications of population decline and stress, the US Fish and Wildlife Service has listed the polar bear as threatened and found that listing the Pacific walrus as threatened or endangered is warranted. Meanwhile, the National Marine Fisheries Service has listed ringed and bearded seals as threatened. The chances of an oil spill in these fragile waters are very real, and the technology for oil cleanup in remote, ice-choked waters does not exist. There is currently no way to adequately respond to oil spills in solid and broken ice conditions and a large spill could cause long-lasting and devastating sociocultural impacts, including contamination of food and water, erosion of community integrity and identity, and substantial impairment to subsistence due to animal loss or changes in migration routes and behavior. Mitigation measures to prevent adverse impacts on the Arctic Ocean environment and wildlife have not been adequately or realistically described.

In addition, Arctic oil and gas pose a major climate threat. Producing and burning projected technically recoverable oil and gas reserves in the Arctic Ocean has the potential to release 15.8 billion tons of CO2 (4.31 GtC) into the atmosphere (equivalent to the CO2 released by all forms of transportation in the US for nine years). Given the difficulty of accessing oil and gas in the Arctic and the tremendously high environmental risks associated with a possible oil spill, it makes sense to leave Arctic Ocean oil and gas in the ground. Audubon’s position is that leasing in the Chukchi Sea should not be permitted until: the needed research has been conducted, potential impacts and mitigation measures have been adequately addressed, effective oil spill clean-up technologies have been demonstrated and proven, critical habitat has been designated for all ESA species and the US and world have adopted a climate plan that adequately reduces CO2 emissions. As part of Audubon’s effort to protect the Arctic Ocean, Audubon has engaged in an intensive effort with our conservation partners to identify and map the most important ecological and subsistence use areas in the Chukchi and Beaufort seas and highlight the need to protect them.

Those findings, based on the best available science, can be found here . What You Can Do Join the Audubon Action Alert Network to receive periodic email alerts on urgent Arctic, Alaska, and national conservation issues as they arise. Donate online now to Audubon Alaska to support our science and policy work in the Arctic. Read More “ Alaska’s Important Bird Areas and Chukchi Sea Oil ” – a blog article from the editors of Birder’s World magazine Audubon’s November 2010 comments on the draft supplemental environmental impact statement on Lease Sale 193 (oil and gas leases in Alaska’s Chukchi Sea) Our October 2010 letter to the US Geological Survey providing comment on a science gap analysis for the Arctic Ocean Downloadable Resources Arctic Ocean - Marine Biodiversity Wiki Marine Biodiversity Wiki Local environment Definition and basic facts The Arctic Ocean consists of a deep Ocean Basin, the broad shelves of the Barents, Kara, Laptev, East Siberian, Chukchi and Beaufort Seas, the White Sea, the Lincoln Sea and the narrow shelf off Canadian Arctic Archipelago and northern Greenland [1] .

Its spatial extent is constrained by the Fram Strait, the western limit of the Barents Sea, the Bering Strait and the Canadian Archipelago (Fig. 1). Figure 1: Arctic Ocean and its constituent seas. Red dotted line indicates the limits of the Arctic Ocean. Main basins of the deep Arctic Ocean basin: NB – Nansen Basin, AB – Amundsen Basin, MB – Makarov Basin, CB – Canada Basin. The bathymetric map is based on IBCAO model v.2. [2] Arctic Ocean and its constituent seas make around 3 % of the total ocean area and only about 1 % of the volume. The Arctic Ocean is the shallowest (mean depth 1361 m) and has significantly larger continental shelves than other oceans. The deep central Arctic Ocean Basin consists of four abyssal plains separated by submarine ridges. The abyssal plains make 12 %, while ridges make 16 % of the total area of the Arctic Ocean [1] . Lomonosov Ridge divide the Arctic Basin into two major sub-basins: Eurasian Basin and Amerasian Basin.

Gakkel Ridge subdivides Eurasian Basin into Amundsen and Nansen Basins, while the Alpha-Mendelejev Ridge subdivides Amerasian Basin into Canada and Makarov Basins (Fig. 1). Continental shelves encompass broad shelves of Eurasia and narrow shelves off North America and northern Greenland and altogether make up as much as 53 % of the total area of the Arctic Ocean. The Barents Sea is the largest of the epicontinental seas. The Laptev and East Siberian Seas are the shallowest (mean depths – 48 and 58 m, respectively). The Lincoln Sea and the adjacent area of the Northern Canadian Arctic Archipelago are the deepest portions of the Arcic Ocean shelve seas (mean depths – 257 and 338 m, respectively). Arctic Ocean is nearly landlocked, the only connections to the other oceans are: 1) Bering Strait (depth 45 m), 2) Canadian Archipelago (depth 220 m) and 3) Fram Strait (depth 2600 m).

Stratification and circulation Figure 2: Stratification of the Arctic Ocean water masses and seawater exchange with Pacific and Atlantic Oceans. (modified from MacDonald and Bewers [3] ) The stratification in the Arctic Ocean is maintained by the fresh water dynamics. The major freshwater sources include: rivers (Arctic Ocean receives around 11 % of the global river runoff discharge), precipitation and ice melt. The low- salinity water from Pacific Ocean inflows via Bering Strait. The low-saline, cold surface waters occupy the upper ~ 50 m and form PML (Polar Mixed Layer) (Fig. 2). Polar halocline (a layer of cold water with a steep salinity gradients) forms below PML and limits the exchange between surface and deep ocean water masses. Deeper water masses are formed by transformed Atlantic waters. The dominant features of the surface circulation are the clockwise Beaufort Gyre (over the Canadian Basin) and the Transpolar Drift (flowing from the Siberian coast towards the Fram Strait) (Fig. 3). The cold and low salinity Arctic surface waters are exported to the North Atlantic Ocean by East Greenland Current and through the Canadian Archipelago.

Warm and high salinity Atlantic water inflow the Arctic Ocean via the Fram Strait and the Barents Sea. Figure 3: Surface circulation and sea ice extent in the Arctic Ocean. A graphic produced by Philippe Rekacewicz, (UNEP/GRID-Arendal) and available at (Last visited March 11, 2009) Sea ice The polar halocline isolates surface water masses and sea-ice from warm deep water and thus acts as a determining factor for the existence of all-year sea ice cover. The ocean’s interior is all year covered with perennial (multi-year) pack ice, while seasonal (first-year) ice-cover is formed on the marginal seas from October to June. The spatial extent of sea ice varies from 14-15 mln km2 in March to 6-7 mln km2 in September (Fig. 3). The inflows of warm Atlantic waters usually keeps the southern part of the Barents sea ice-free year round. The average thickness of sea ice in the Arctic Ocean is about 3 m. Land-fast ice (up to 2 m in thickness) grows seaward from the shore and usually extends to the 20 m isobath.

Two forms of open water areas can occur in the winter ice-cover: 1) flaw lead systems – discontinuities between the land-fast ice and off-shore sea-ice or 2) polynyas – where ice is carried away by winds or currents or melted by the local convection of warm deep water masses. Primary production Primary productivity in the Arctic Ocean is relatively low, but can vary considerably between regions [4] . The productivity of the central Arctic Basin is among the lowest recorded in the world seas. The primary production is limited by the presence of multiyear ice- cover and very short growing season. The Siberian shelf seas also exhibit low productivity that is mostly nutrient-limited: the Siberian rivers are phosphorous-poor and the multi-year ice covers the shelf break, thus hindering the wind-driven upwelling of nutrient-rich deep waters at the shelf edge. In contrast, Barents Sea (that is kept ice-free by the inflows of warm Atlantic waters) and Chukchi Sea (that is supplied with nutrient-rich Bering Sea waters) can have primary production several times higher that the Arctic Ocean average (Table 1). Table 1.

Average annual primary production (av PP [gC m-2 y-1]) and total areal primary production (tot PP [106 t C]) in the Arctic Ocean and its constituent seas. After several authors compiled by Sakshaug [4] area >329 Specific biodiversity issues Arctic Ocean fauna is relatively young and comprise few endemics, it is mostly composed of species of Pacific or Atlantic affinity [5] .

The origin and evolution of the arctic biota was summarized by Dunton [5] : north polar sea originated as a large northern embayment of the North Pacific in the Mesozoic, in late Cretaceous large connections to subtropical Gulf of Mexico and to tropical Tethys sea were developed (that could result in some subtropical taxa migrations and may explain the origin of some Arctic species with phylogenetic affinities with warm-water taxa) about the end of Cretaceous the deep-water connection (and the exchange of bathyal and abyssal fauna) between Arctic Ocean and North Pacific was closed by continental plate movements, deep-water seaways between Arctic Ocean and North Atlantic (and the migration of Atlantic taxa) occurred by the end of Eocene, that coincided with a large cooling of the northern high latitude areas (temperature decreased to below 10˚C) successive cooling (temperatures dropped to below 5˚C in late Miocene) and the exchange with the North Atlantic led to the development of cool-temperate arctic biota of the Atlantic character in late Pliocene the Bering Land Bridge was breached and the shallow water passage between Pacific Ocean and Arctic Ocean opened – the arctic fauna was strongly supplemented by migrants from Pacific

 Ocean perennial ice cover developed in Pleistocene, when the Arctic was subjected to numerous glacial and interglacial intervals; during the maximum of the last major glaciation (18 ky ago) the Arctic shelves were either covered with permanent ice sheets or emergent and so the shallow water fauna was nearly completely eradicated.

Arctic shallow seas are now considered to remain in a phase of colonization (after the last deglaciation, i.e. for the last 6-14 ky) [5] . Figure 4: Numbers of invertebrate species recorded in the Arctic deep basin and in the eurasian Arctic marginal seas according to Sirenko [6] There are only few records of the fauna of the deep Arctic basin, and they are limited to a low number of samples. All the up-to date records show very low biomass (from 5 to 32 mg C m-2) and species diversity (from 1 to 11 species per 0.02 m2) of macrozoobenthos dwelling in arctic deep basins [7] . The fauna of the Siberian shallow shelf seas is also relatively impoverished as it is confronted with the low primary productivity and physical stress produced by massive riverine inflows. The productive waters of the Barents Sea host much higher numbers of species that other arctic regions [8] (Fig. 4).

The local hot-spots of both productivity and biodiversity in the Arctic include flaw lead systems, polynyas, areas of oceanographic fronts where mixing between cold polar and temperate waters occur and marginal ice zone [9] . Threats Figure 5: The decrease of Arctic Ocean multiyear sea ice: minimum sea-ice extent in 1982 and 2007, and projections of the future successive decrease of sea-ice extent within this century (according to the Arctic Climate Impact Assessment ). The graphic was produced by Hugo Ahlenius (UNEP/GRID-Arendal) and is available at . (Last visited March 11, 2009). The main threats to biodiversity in this region are generated by the potential effects of the global warming. Land-surface air temperatures increased with an average rate of 0.09˚C/decade in the Arctic form 1900 to 2003 that is greater than overall trend documented for the northern hemisphere (0.06˚C/decade) [10] . The warming is accompanied by the decrease of both spatial extent and thickness of the Arctic sea-ice cover (Fig. 5).

The possible effects of the climate warming on the marine ecosystems of the Arctic Ocean were summarized by Loeng et al [9] and include: poleward shift in species distributions – both southern limits of distribution of coldwater species and northern limits of warm water temperate species will move northward, increase of primary productivity (driven by the removal of light limitation after the disappearance of sea ice cover) and possible change of timing of the blooms – that can affect the pelago-benthic coupling processes, the dramatic decrease of the sea-ice extent will affect the sea ice ecosystems . The decline of the sea-ice extent will improve the accessibility of the Arctic Ocean to shipping and exploration of the natural resources (extensive fishing and exploration of large oil and gas reserves). That will certainly largely increase the anthropogenic pressure on the relatively pristine ecosystems of the Arctic Oceans. References ↑ 1.0 1.1 Jakobsson, M., 2002, Hypsometry and volume of the Arctic Ocean and its constituent's seas, Geochemistry Geophysics Geosystems, v. 3, no. 2. ↑ Jakobsson, M., R. Macnab, L. Mayer, R. Anderson, M. Edwards, J.

Hatzky, H. W. Schenke, and P. Johnson (2008), An improved bathymetric portrayal of the Arctic Ocean: Implications for ocean modeling and geological, geophysical and oceanographic analyses, Geophysical Research Letters, DOI: doi: 10.1029/2008gl033520. ↑ MacDonald, R.W., Bewers, J.M., 1996, Contaminants in the arctic marine environment: priorities for protection. ICES J Mar Sci 53: 537-563 ↑ 4.0 4.1 Sakshaug, E., 2003, Primary and Secondary Production in the Arctic Seas. in: Stein, R., MacDonald, R.W., The organic carbon cycle in the Arctic Ocean. Springer, pp 57-81 ↑ 5.0 5.1 5.2 Dunton, K., 1992, Arctic biogeography: the paradox of the marine benthic fauna and flora. TREE 7, 183-189.

↑ Sirenko, B.I., 2001, List of species of free-living invertebrates of eurasian arctic seas and adjacent deep waters. Explorations of the fauna of the seas 51(59) St Petersburg, 1-129. ↑ Klages, M., Boetius A., Christensen, J.P., Deubel, H., Piepenburg, D., Schewe, I., Soltwedel, T., 2003, The benthos of Arctic Seas and its role for the organic carbon cycle at the seafloor. in: Stein, R., MacDonald, R.W., The organic carbon cycle in the Arctic Ocean. Springer, pp 139-167. ↑ Sirenko, B.I., 2001, List of species of free-living invertebrates of eurasian arctic seas and adjacent deep waters. Explorations of the fauna of the seas 51(59) St Petersburg, 1-129.

↑ 9.0 9.1 Loeng H, Brander K, Carmack E, Denisenko S and others (2005) Marine systems. In: Symon C, Arris L, Heal B (eds) Arctic climate impact assessment, ACIA. Cambridge University Press, Cambridge, p 453–538. available at ↑ McBean, G, Alekseev, G., Chen, D., Forland, E. and others (2005) Arctic Climate: Past and Present. In: Symon C, Arris L, Heal B (eds) Arctic climate impact assessment, ACIA. Cambridge University Press, Cambridge, p 21- 60. available at See also Shell gives up on all but one Chukchi Sea lease | The Independent Barents Observer The Independent Barents Observer Shell vessels in Alaska.

Photo: Shell.com Shell gives up on all but one Chukchi Sea lease Royal Dutch Shell has decided to give up all but one of its federal offshore leases in the Chukchi Sea, bringing what appears to be an anticlimactic end to its multibillion-dollar effort to turn those icy Arctic waters off northwestern Alaska into a new oil-producing frontier. By Alaska Dispatch News May 11, 2016 “After extensive consideration and evaluation, we have made the decision to relinquish all but one of our federal offshore leases in Alaska’s Chukchi Sea. This action is consistent with our earlier decision not to explore offshore Alaska for the foreseeable future,” company spokesman Curtis Smith said in an email on Monday. The company had spent over $2 billion acquiring Chukchi leases in a record-breaking federal lease sale held in 2008. The company conducted two drilling seasons, in 2012 and 2015, that were fraught with mishaps and legal and public-relations challenges. Drilling in 2015, at a well in a prospect called Burger, yielded what Shell characterized as disappointing results, and the company announced in September that it had decided to shelve its entire offshore Alaska program .

The decision to relinquish leases “reflects the outcome of the Burger J well and the high costs associated with the project,” Smith said, referring to the well drilled last year. “While we support regulations that enforce high safety and environmental standards, the unpredictable federal regulatory environment for the Alaska Outer Continental Shelf also made it difficult to operate efficiently.” The Chukchi Sea leases were scheduled to expire in 2020. Evaluations of future leases The one lease that Shell intends to retain holds the now-plugged Burger J well that was drilled last summer. Shell still holds leases in the Beaufort Sea off northern Alaska that were acquired for a combined $84 million in federal sales held in 2005 and 2007. Shell also holds leases in Alaska state territory, some of them transferred when the Anglo-Dutch oil giant bought the BG Group for nearly $70 billion last year. Those leases might be dropped as well. “Separate evaluations are underway for our federal offshore leases in the Beaufort Sea. We also are evaluating our state leases and our interest in the Alaska Foothills acreage we acquired from BG earlier this year,” Smith said in his email. Gov. Bill Walker lamented the latest Shell decision.

“The news that Shell will be relinquishing all but one of its offshore leases in the Chukchi Sea is disappointing. With a pipeline that is three-quarters empty and a $4 billion budget deficit, it is absolutely critical that we find safe and responsible opportunities to drill for more oil both on-shore and off-shore in Alaska,” he said in a statement. “I will continue to work with local stakeholders, the federal government and industry to develop our state’s rich natural resources in order to bring more jobs and revenue to Alaska.” But a critic of Shell’s offshore operations said the company’s decision to give back the leases was good news. “Today we are an important step closer to a sustainable future for the Arctic Ocean. After spending more than a decade and billions of dollars, even Shell has had to recognize that offshore oil exploration in the Arctic is not worth the environmental or economic risks,” Michael LeVine, senior Pacific counsel for the environmental group Oceana, said in a statement.

Alaska operations LeVine noted that other companies — ConocoPhillips, Iona, Statoil, Total, EnCana and Armstrong – have also given up offshore Arctic leases, and that of the more than 480 tracts auctioned off in 2008, only about a fifth will be active. Relinquishment of Shell’s leases has occurred in stages. As of Monday, the Bureau of Ocean Energy Management’s Alaska office had not received notice about Shell’s latest decision to give up all but one of its Chukchi leases, said John Callahan, a spokesman for the federal agency. But Shell had given up leases on 36 tracts in March and another 125 in April, leaving 114 in active status after those two relinquishment phases, Callahan said. Shell reported that it spent over $7 billion in its overall Alaska exploration program but managed to drill only one well to full depth – Burger J. The program was fraught with setbacks, including the 2012 grounding of Shell’s Kulluk drillship , an event that caused so much damage that Shell decided to forego repairs to the vessel. Still, Shell is not completely done with its Alaska operations.

It still has to retrieve anchors that were left at now-capped wells it drilled in 2012. That activity is forthcoming, Smith said. “In the summer months of 2016, we will remove the remaining equipment from the drilling sites in Alaska,” he said in his email. “We continue to believe offshore Alaska and the broader Arctic have strong exploration potential and are areas that could ultimately be important sources of energy to the State of Alaska, the United States, and the world.” Smith also said Shell has not dropped its appeal of an October decision by the federal government that denied the company’s request for an effective extension on Chukchi and Beaufort leases. That decision was issued by BOEM’s sister Interior Department agency, the Bureau of Safety and Environmental Enforcement. This story is posted on Independent Barents Observer as part of Eye on the Arctic , a collaborative partnership between public and private circumpolar media organizations. Sections

Question: The Chukchi, Beaufort, and Barents are all seas in which ocean?
Answer: Arctic